RESUMO
To report an anomalous communication of the median nerve with the ulnar nerve in the right upper limb of formalin-fixed adult male cadaver and compare it to those reported in similar studies that were retrieved after a wide review of the literature. During a routine cadaveric dissection of a formalin-fixed cadaver in our laboratory, we encountered a neuro-anatomical variation. The forearm was exposed and carefully dissected and examined for any further anatomical variations. The Martin-Gruber branch originated from the median nerve close to the cubital fossa approximately at the junction between the upper one fourth and the lower three fourth of the forearm. The nerve which was related lateral to the ulnar artery then descended downwards deep to the ulnar artery and emerged on its medial border before it communicated with the ulnar nerve. The anastomoses between median and ulnar nerves are clinically relevant. By identifying the existence of different types of anastomoses, mistakes in the diagnosis of peripheral nerve lesions or compression neuropathies in the forearm can be avoided